<?php
/**
 * CMssqlSchema class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @author Christophe Boulain <Christophe.Boulain@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2011 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CMssqlSchema is the class for retrieving metadata information from a MS SQL Server database.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @author Christophe Boulain <Christophe.Boulain@gmail.com>
 * @version $Id: CMssqlSchema.php 3099 2011-03-19 01:26:47Z qiang.xue $
 * @package system.db.schema.mssql
 * @since 1.0.4
 */
class CMssqlSchema extends CDbSchema
{
    const DEFAULT_SCHEMA = 'dbo';
    
    /**
     * @var array the abstract column types mapped to physical column types.
     * @since 1.1.6
     */
    public $columnTypes = array ('pk' => 'int IDENTITY PRIMARY KEY', 'string' => 'varchar(255)', 'text' => 'text', 'integer' => 'int', 'float' => 'float', 'decimal' => 'decimal', 'datetime' => 'datetime', 'timestamp' => 'timestamp', 'time' => 'time', 'date' => 'date', 'binary' => 'binary', 'boolean' => 'bit' );
    
    /**
     * Quotes a table name for use in a query.
     * A simple table name does not schema prefix.
     * @param string $name table name
     * @return string the properly quoted table name
     * @since 1.1.6
     */
    public function quoteSimpleTableName($name)
    {
        return '[' . $name . ']';
    }
    
    /**
     * Quotes a column name for use in a query.
     * A simple column name does not contain prefix.
     * @param string $name column name
     * @return string the properly quoted column name
     * @since 1.1.6
     */
    public function quoteSimpleColumnName($name)
    {
        return '[' . $name . ']';
    }
    
    /**
     * Compares two table names.
     * The table names can be either quoted or unquoted. This method
     * will consider both cases.
     * @param string $name1 table name 1
     * @param string $name2 table name 2
     * @return boolean whether the two table names refer to the same table.
     */
    public function compareTableNames($name1, $name2)
    {
        $name1 = str_replace ( array ('[', ']' ), '', $name1 );
        $name2 = str_replace ( array ('[', ']' ), '', $name2 );
        return parent::compareTableNames ( strtolower ( $name1 ), strtolower ( $name2 ) );
    }
    
    /**
     * Resets the sequence value of a table's primary key.
     * The sequence will be reset such that the primary key of the next new row inserted
     * will have the specified value or 1.
     * @param CDbTableSchema $table the table schema whose primary key sequence will be reset
     * @param mixed $value the value for the primary key of the next new row inserted. If this is not set,
     * the next new row's primary key will have a value 1.
     * @since 1.1.6
     */
    public function resetSequence($table, $value = null)
    {
        if ($table->sequenceName !== null) {
            $db = $this->getDbConnection ();
            if ($value === null)
                $value = $db->createCommand ( "SELECT MAX(`{$table->primaryKey}`) FROM {$table->rawName}" )->queryScalar ();
            $value = ( int ) $value;
            $name = strtr ( $table->rawName, array ('[' => '', ']' => '' ) );
            $db->createCommand ( "DBCC CHECKIDENT ('$name', RESEED, $value)" )->execute ();
        }
    }
    
    private $_normalTables = array (); // non-view tables
    /**
     * Enables or disables integrity check.
     * @param boolean $check whether to turn on or off the integrity check.
     * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
     * @since 1.1.6
     */
    public function checkIntegrity($check = true, $schema = '')
    {
        $enable = $check ? 'CHECK' : 'NOCHECK';
        if (! isset ( $this->_normalTables [$schema] ))
            $this->_normalTables [$schema] = $this->findTableNames ( $schema, false );
        $db = $this->getDbConnection ();
        foreach ( $this->_normalTables [$schema] as $tableName ) {
            $tableName = $this->quoteTableName ( $tableName );
            $db->createCommand ( "ALTER TABLE $tableName $enable CONSTRAINT ALL" )->execute ();
        }
    }
    
    /**
     * Loads the metadata for the specified table.
     * @param string $name table name
     * @return CMssqlTableSchema driver dependent table metadata. Null if the table does not exist.
     */
    protected function loadTable($name)
    {
        $table = new CMssqlTableSchema ();
        $this->resolveTableNames ( $table, $name );
        //if (!in_array($table->name, $this->tableNames)) return null;
        $table->primaryKey = $this->findPrimaryKey ( $table );
        $table->foreignKeys = $this->findForeignKeys ( $table );
        if ($this->findColumns ( $table )) {
            return $table;
        } else
            return null;
    }
    
    /**
     * Generates various kinds of table names.
     * @param CMssqlTableSchema $table the table instance
     * @param string $name the unquoted table name
     */
    protected function resolveTableNames($table, $name)
    {
        $parts = explode ( '.', str_replace ( array ('[', ']' ), '', $name ) );
        if (($c = count ( $parts )) == 3) {
            // Catalog name, schema name and table name provided
            $table->catalogName = $parts [0];
            $table->schemaName = $parts [1];
            $table->name = $parts [2];
            $table->rawName = $this->quoteTableName ( $table->catalogName ) . '.' . $this->quoteTableName ( $table->schemaName ) . '.' . $this->quoteTableName ( $table->name );
        } elseif ($c == 2) {
            // Only schema name and table name provided
            $table->name = $parts [1];
            $table->schemaName = $parts [0];
            $table->rawName = $this->quoteTableName ( $table->schemaName ) . '.' . $this->quoteTableName ( $table->name );
        } else {
            // Only the name given, we need to get at least the schema name
            //if (empty($this->_schemaNames)) $this->findTableNames();
            $table->name = $parts [0];
            $table->schemaName = self::DEFAULT_SCHEMA;
            $table->rawName = $this->quoteTableName ( $table->schemaName ) . '.' . $this->quoteTableName ( $table->name );
        }
    }
    
    /**
     * Gets the primary key column(s) details for the given table.
     * @param CMssqlTableSchema $table table
     * @return mixed primary keys (null if no pk, string if only 1 column pk, or array if composite pk)
     */
    protected function findPrimaryKey($table)
    {
        $kcu = 'INFORMATION_SCHEMA.KEY_COLUMN_USAGE';
        $tc = 'INFORMATION_SCHEMA.TABLE_CONSTRAINTS';
        if (isset ( $table->catalogName )) {
            $kcu = $table->catalogName . '.' . $kcu;
            $tc = $table->catalogName . '.' . $tc;
        }
        
        $sql = <<<EOD
		SELECT k.column_name field_name
			FROM {$this->quoteTableName($kcu)} k
		    LEFT JOIN {$this->quoteTableName($tc)} c
		      ON k.table_name = c.table_name
		     AND k.constraint_name = c.constraint_name
		   WHERE c.constraint_type ='PRIMARY KEY'
		   	    AND k.table_name = :table
				AND k.table_schema = :schema
EOD;
        $command = $this->getDbConnection ()->createCommand ( $sql );
        $command->bindValue ( ':table', $table->name );
        $command->bindValue ( ':schema', $table->schemaName );
        $primary = $command->queryColumn ();
        switch (count ( $primary )) {
            case 0 : // No primary key on table
                $primary = null;
                break;
            case 1 : // Only 1 primary key
                $primary = $primary [0];
                break;
        }
        return $primary;
    }
    
    /**
     * Gets foreign relationship constraint keys and table name
     * @param CMssqlTableSchema $table table
     * @return array foreign relationship table name and keys.
     */
    protected function findForeignKeys($table)
    {
        $rc = 'INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS';
        $kcu = 'INFORMATION_SCHEMA.KEY_COLUMN_USAGE';
        if (isset ( $table->catalogName )) {
            $kcu = $table->catalogName . '.' . $kcu;
            $rc = $table->catalogName . '.' . $rc;
        }
        
        //From http://msdn2.microsoft.com/en-us/library/aa175805(SQL.80).aspx
        $sql = <<<EOD
		SELECT
		     KCU1.CONSTRAINT_NAME AS 'FK_CONSTRAINT_NAME'
		   , KCU1.TABLE_NAME AS 'FK_TABLE_NAME'
		   , KCU1.COLUMN_NAME AS 'FK_COLUMN_NAME'
		   , KCU1.ORDINAL_POSITION AS 'FK_ORDINAL_POSITION'
		   , KCU2.CONSTRAINT_NAME AS 'UQ_CONSTRAINT_NAME'
		   , KCU2.TABLE_NAME AS 'UQ_TABLE_NAME'
		   , KCU2.COLUMN_NAME AS 'UQ_COLUMN_NAME'
		   , KCU2.ORDINAL_POSITION AS 'UQ_ORDINAL_POSITION'
		FROM {$this->quoteTableName($rc)} RC
		JOIN {$this->quoteTableName($kcu)} KCU1
		ON KCU1.CONSTRAINT_CATALOG = RC.CONSTRAINT_CATALOG
		   AND KCU1.CONSTRAINT_SCHEMA = RC.CONSTRAINT_SCHEMA
		   AND KCU1.CONSTRAINT_NAME = RC.CONSTRAINT_NAME
		JOIN {$this->quoteTableName($kcu)} KCU2
		ON KCU2.CONSTRAINT_CATALOG =
		RC.UNIQUE_CONSTRAINT_CATALOG
		   AND KCU2.CONSTRAINT_SCHEMA =
		RC.UNIQUE_CONSTRAINT_SCHEMA
		   AND KCU2.CONSTRAINT_NAME =
		RC.UNIQUE_CONSTRAINT_NAME
		   AND KCU2.ORDINAL_POSITION = KCU1.ORDINAL_POSITION
		WHERE KCU1.TABLE_NAME = :table
EOD;
        $command = $this->getDbConnection ()->createCommand ( $sql );
        $command->bindValue ( ':table', $table->name );
        $fkeys = array ();
        foreach ( $command->queryAll () as $info ) {
            $fkeys [$info ['FK_COLUMN_NAME']] = array ($info ['UQ_TABLE_NAME'], $info ['UQ_COLUMN_NAME'] );
        
        }
        return $fkeys;
    }
    
    /**
     * Collects the table column metadata.
     * @param CMssqlTableSchema $table the table metadata
     * @return boolean whether the table exists in the database
     */
    protected function findColumns($table)
    {
        $where = array ();
        $where [] = "TABLE_NAME='" . $table->name . "'";
        if (isset ( $table->catalogName ))
            $where [] = "TABLE_CATALOG='" . $table->catalogName . "'";
        if (isset ( $table->schemaName ))
            $where [] = "TABLE_SCHEMA='" . $table->schemaName . "'";
        $sql = "SELECT *, columnproperty(object_id(table_schema+'.'+table_name), column_name, 'IsIdentity') as IsIdentity " . "FROM INFORMATION_SCHEMA.COLUMNS WHERE " . join ( ' AND ', $where );
        if (($columns = $this->getDbConnection ()->createCommand ( $sql )->queryAll ()) === array ())
            return false;
        
        foreach ( $columns as $column ) {
            $c = $this->createColumn ( $column );
            if (is_array ( $table->primaryKey ))
                $c->isPrimaryKey = in_array ( $c->name, $table->primaryKey );
            else
                $c->isPrimaryKey = strcasecmp ( $c->name, $table->primaryKey ) === 0;
            
            $c->isForeignKey = isset ( $table->foreignKeys [$c->name] );
            $table->columns [$c->name] = $c;
            if ($c->autoIncrement && $table->sequenceName === null)
                $table->sequenceName = $table->name;
        }
        return true;
    }
    
    /**
     * Creates a table column.
     * @param array $column column metadata
     * @return CDbColumnSchema normalized column metadata
     */
    protected function createColumn($column)
    {
        $c = new CMssqlColumnSchema ();
        $c->name = $column ['COLUMN_NAME'];
        $c->rawName = $this->quoteColumnName ( $c->name );
        $c->allowNull = $column ['IS_NULLABLE'] == 'YES';
        if ($column ['NUMERIC_PRECISION_RADIX'] !== null) {
            // We have a numeric datatype
            $c->size = $c->precision = $column ['NUMERIC_PRECISION'] !== null ? ( int ) $column ['NUMERIC_PRECISION'] : null;
            $c->scale = $column ['NUMERIC_SCALE'] !== null ? ( int ) $column ['NUMERIC_SCALE'] : null;
        } elseif ($column ['DATA_TYPE'] == 'image' || $column ['DATA_TYPE'] == 'text')
            $c->size = $c->precision = null;
        else
            $c->size = $c->precision = ($column ['CHARACTER_MAXIMUM_LENGTH'] !== null) ? ( int ) $column ['CHARACTER_MAXIMUM_LENGTH'] : null;
        $c->autoIncrement = $column ['IsIdentity'] == 1;
        
        $c->init ( $column ['DATA_TYPE'], $column ['COLUMN_DEFAULT'] );
        return $c;
    }
    
    /**
     * Returns all table names in the database.
     * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
     * If not empty, the returned table names will be prefixed with the schema name.
     * @param boolean $includeViews whether to include views in the result. Defaults to true.
     * @return array all table names in the database.
     * @since 1.0.4
     */
    protected function findTableNames($schema = '', $includeViews = true)
    {
        if ($schema === '')
            $schema = self::DEFAULT_SCHEMA;
        if ($includeViews)
            $condition = "TABLE_TYPE in ('BASE TABLE','VIEW')";
        else
            $condition = "TABLE_TYPE='BASE TABLE'";
        $sql = <<<EOD
SELECT TABLE_NAME, TABLE_SCHEMA FROM [INFORMATION_SCHEMA].[TABLES]
WHERE TABLE_SCHEMA=:schema AND $condition
EOD;
        $command = $this->getDbConnection ()->createCommand ( $sql );
        $command->bindParam ( ":schema", $schema );
        $rows = $command->queryAll ();
        $names = array ();
        foreach ( $rows as $row ) {
            if ($schema == self::DEFAULT_SCHEMA)
                $names [] = $row ['TABLE_NAME'];
            else
                $names [] = $schema . '.' . $row ['TABLE_SCHEMA'] . '.' . $row ['TABLE_NAME'];
        }
        
        return $names;
    }
    
    /**
     * Creates a command builder for the database.
     * This method overrides parent implementation in order to create a MSSQL specific command builder
     * @return CDbCommandBuilder command builder instance
     */
    protected function createCommandBuilder()
    {
        return new CMssqlCommandBuilder ( $this );
    }
    
    /**
     * Builds a SQL statement for renaming a DB table.
     * @param string $table the table to be renamed. The name will be properly quoted by the method.
     * @param string $newName the new table name. The name will be properly quoted by the method.
     * @return string the SQL statement for renaming a DB table.
     * @since 1.1.6
     */
    public function renameTable($table, $newName)
    {
        return "sp_rename '$table', '$newName'";
    }
    
    /**
     * Builds a SQL statement for renaming a column.
     * @param string $table the table whose column is to be renamed. The name will be properly quoted by the method.
     * @param string $name the old name of the column. The name will be properly quoted by the method.
     * @param string $newName the new name of the column. The name will be properly quoted by the method.
     * @return string the SQL statement for renaming a DB column.
     * @since 1.1.6
     */
    public function renameColumn($table, $name, $newName)
    {
        return "sp_rename '$table.$name', '$newName', 'COLUMN'";
    }
    
    /**
     * Builds a SQL statement for changing the definition of a column.
     * @param string $table the table whose column is to be changed. The table name will be properly quoted by the method.
     * @param string $column the name of the column to be changed. The name will be properly quoted by the method.
     * @param string $type the new column type. The {@link getColumnType} method will be invoked to convert abstract column type (if any)
     * into the physical one. Anything that is not recognized as abstract type will be kept in the generated SQL.
     * For example, 'string' will be turned into 'varchar(255)', while 'string not null' will become 'varchar(255) not null'.
     * @return string the SQL statement for changing the definition of a column.
     * @since 1.1.6
     */
    public function alterColumn($table, $column, $type)
    {
        $type = $this->getColumnType ( $type );
        $sql = 'ALTER TABLE ' . $this->quoteTableName ( $table ) . ' ALTER COLUMN ' . $this->quoteColumnName ( $column ) . ' ' . $this->getColumnType ( $type );
        return $sql;
    }
}
